Free tools for sole traders
Calculators built on HMRC’s own published figures. No account needed, and nothing you type is stored.
HMRC exchange rate calculator
Convert an amount in euros, dollars or any other currency into pounds at HMRC’s monthly exchange rate, for any month since January 2022.
Self-employed tax calculator
Estimate the Income Tax and National Insurance on your profit as a sole trader, for 2026 to 2027 or 2025 to 2026, in Scotland or the rest of the UK.
Payments on account calculator
Work out from last year’s Self Assessment bill whether you need to make payments on account, how much each one is, and what you pay on 31 January.